That brown crumbly mixture of minerals, organic matter, gases, liquids and countless tiny organisms better known as soil, is a dynamic ecosystem that supports life on Earth. Not only is it a medium for plant growth, it also stores, supplies and purifies water; modifies the Earth’s atmosphere; and is habitat for billions of soil creatures. Pretty noble for a substance that we walk all over every day, but also one that gardeners know to give serious attention to.

Healthy soil is a big part of the equation when it comes to growing healthy plants. (For more info on healthy soil, take a look at our post on What Makes Soil Healthy). Along with light and water, soil is a crucial part of the growing garden equation. And by paying attention to it’s nutrient content, texture, and proportion of organic matter, gardeners can play a positive role in influencing soil’s health.

Organic matter is the key in this process of building healthy soil. It’s the one component that we can directly affect and the proportion of it in soil has a clear influence on texture and nutrients. And while the process of increasing organic matter isn’t a quick endeavor, by incorporating cover crops into your garden on a regular basis you can easily start making an impact.

Organic matter is decomposed plant material that enhances water and nutrient holding capacity and improves soil structure. The billions of soil microbes interacting with this plant material is key to the process of building healthy soil. For instance, when cover crops are incorporated into the soil, larger soil animals like mites break it into smaller pieces that fungi and bacteria start to decompose. This decomposition gives off nutrients, some of which the critters use for energy and some of which becomes available to plants. In addition, when microbes die and decompose, the nutrients contained within them also become available to plants.

Soil microbes also improve soil structure and texture by forming channels and pores, concentrating fine soil particles together into aggregates and by breaking up and mixing organic matter throughout the soil. Good soil structure helps reduce compaction and surface crusting and increases water infiltration and storage.

If there’s an abundance of organic matter being incorporated into the soil through the use of cover crops, the number of microbes in the soil increases. This is because the microbes can use the organic matter as a source of energy and so they grow and multiply. Which means more nutrients and moisture available to plants in this beneficial cycle.

It’s all pretty simple, really. The microbes in the soil need food, water and air to survive. By growing and incorporating cover crops, we’re providing the source of their food. Good aeration, soil moisture and a neutral soil pH (acid level) help provide the conditions the microbes need to do the work of turning the cover crop organic matter into nutrients that are then available to our plants. Our plants grow tall and strong and produce a good harvest. Everyone eats!